Silica-based materials have been put to a variety of uses as materials with their characteristics applied. Examples of the uses are a filler for liquid chromatography, a base for cosmetics, a catalyst, a catalyst support, a flow adjuster and a diluent. As one of means for attaining physical properties such as a high specific surface area meeting requirements for these uses, a silica-based material may be modified to be porous, but in this case, the mechanical strength of the silica-based material is reduced. On the other hand, when a precursor of a silica-based material is calcined at a high temperature for increasing the mechanical strength of the silica-based material, its specific surface area is reduced. In this manner, it is difficult to obtain a silica-based material satisfying conflicting physical properties, i.e., high mechanical strength and a high specific surface area, and a silica-based material meeting both of these requirements has not been obtained yet.
Quartz, that is, one of silica-based materials, is known to be hard and have high mechanical strength. Although quartz is generally superior in mechanical strength, however, it has a small specific surface area (of 1 m2/g or less), and hence, it may not be used for a use requiring a high specific surface area. Although a silica-based material may be synthesized to attain a high specific surface area so as to be used as a catalyst support in some cases, the mechanical strength is sacrificed in such cases, and no silica-based material shows both a high specific surface area and high mechanical strength in these cases.
Patent Literature 1 describes, as a catalyst support for use in producing carboxylic acid ester, silica-alumina-magnesia including 5 to 40 wt % of aluminum in terms of Al2O3, 3 to 30 wt % of magnesium in terms of MgO and 50 to 92 wt % of silicon in terms of SiO2.